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Hi everyone,

I've bought some BUZ901P/906P output devices, which are lateral mosfets from Semelab, I wanted to know if some one has incorporated those devices in the output stage of the amplifier.

They are better or worse than other types of laterals, about parasitc oscillations, and reliability.

Thank you very much for your attention,
Best regards,
Daniel Almeida


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We had an earthquake a couple of years ago that took out a semi manufacturing plant.

ALL production and distribution of Lateral mosFETs STOPPED completely.

This seemed to indicate that we have ONE semi plant making the whole worldwide chips for ALL power lat FETs.

If this is the case then all power lat FETs come out of the same factory.

The different "manufacturers" package them differently.
Does that mean they all perform differently, or the same?
I have one amplifier fitted with BUZ900/BUZ905 and another version of the same amplifier fitted with 2SK135/2SJ50. They were both rebuilt a couple of years ago. The output stage of each amplifier has 8 parallel pairs per channel and they operate without resistors on the output of each transistor.
They both sound excellant but slightly different. The slight difference is that the BUZ devices may give a stronger base whereas the 2SK135/2SJ50 may provide a clearer treble. But the diference is very slight.
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If you go to UK manufacturer Semelab's site, you find the ALFET range of audio Latfets marketed by their distribution company, Magnatec. Go to profusion's site and you see the same range and specifications marketed by them under the EXICON brand. As far as I can tell from Semelab's datasheets, the BUZ series are generally specified for lower power amplifiers (<1kW) whilst the Magnatec and Exicon ranges are are specified for <2kW applications. I can't make sense of that from the range of Vds offered but others may have better information than Semelab's brief website note.

That's not saying they can't be used just as well as each other in suitable supply voltage range applications, which is what people - manufacturers even, have already been doing for years.

A couple of other DIYs have also posted here over the last 2 years, that they were satisfied with the results when they bought the BUZ parts on the price basis, to replace early Hitachi TO3s.

AFAIK, Renesas latfets are still produced in one of a number of Chinese fabs. There is certainly a trickle of fakes coming from China now (surprise, suprise!) and they are mosfets of some description with the moulding detail looking genuine but the marks and performance are quite disappointing according to a couple of suckered customers I spoke to earlier this year.

It's just a guess, but the idea of getting rid of scrap semiconductors and making a small return at the same time must appeal to plant managers trying too hard to be competitive without satisfactory process controls, whatever they are trying to produce.

Have a look at the same general issues in this thread
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